Hybrid Public Key Encryption (HPKE)

Created

  • 2021-11-16

Last Updated

  • 2026-11-10

Available Formats

HPKE KEM Identifiers

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Christopher Wood, Richard Barnes

Reference

Request an Assignment

https://www.iana.org/form/protocol-assignment

Note

The Auth column indicates whether the KEM provides the AuthEncap()/AuthDecap() interface defined in RFC 9180. This interface is not used by RFC-ietf-hpke-hpke-06. New registrations use "yes" only if the specification for the KEM defines AuthEncap() and AuthDecap() for that KEM, and "no" otherwise.

Available Formats

Value KEM Nsecret Nenc Npk Nsk Auth Reference
0x0000 Reserved N/A N/A N/A N/A N/A RFC-ietf-hpke-hpke-06
0x0001-0x000F Unassigned
0x0010 DHKEM(P-256, HKDF-SHA256) 32 65 65 32 yes NISTCurves; RFC 5869
0x0011 DHKEM(P-384, HKDF-SHA384) 48 97 97 48 yes NISTCurves; RFC 5869
0x0012 DHKEM(P-521, HKDF-SHA512) 64 133 133 66 yes NISTCurves; RFC 5869
0x0013 DHKEM(CP-256, HKDF-SHA256) 32 32 32 32 Yes NISTCurves; RFC 6090; draft-irtf-cfrg-dnhpke-01
0x0014 DHKEM(CP-384, HKDF-SHA384) 48 48 48 48 Yes NISTCurves; RFC 6090; draft-irtf-cfrg-dnhpke-01
0x0015 DHKEM(CP-521, HKDF-SHA512) 64 66 66 66 Yes NISTCurves; RFC 6090; draft-irtf-cfrg-dnhpke-01
0x0016 DHKEM(secp256k1, HKDF-SHA256) 32 65 65 32 yes Standards for Efficient Cryptography 2 (SEC 2); draft-wahby-cfrg-hpke-kem-secp256k1-01
0x0017-0x001F Unassigned
0x0020 DHKEM(X25519, HKDF-SHA256) 32 32 32 32 yes RFC 5869; RFC 7748
0x0021 DHKEM(X448, HKDF-SHA512) 64 56 56 56 yes RFC 5869; RFC 7748
0x0022 DHKEM(X25519+Elligator, HKDF-SHA256) 32 32 32 32 yes https://lsd.gnunet.org/lsd0011/; draft-schanzen-hpke-elligator-kem-01
0x0023-0x002F Unassigned
0x0030 X25519Kyber768Draft00 64 1120 1216 2432 no draft-westerbaan-cfrg-hpke-xyber768d00-02
0x0031-0x003F Unassigned
0x0040 ML-KEM-512 32 768 800 64 no draft-connolly-cfrg-hpke-mlkem-04
0x0041 ML-KEM-768 32 1088 1184 64 no draft-connolly-cfrg-hpke-mlkem-04
0x0042 ML-KEM-1024 32 1568 1568 64 no draft-connolly-cfrg-hpke-mlkem-04
0x0043-0x004F Unassigned
0x0050 MLKEM768-P256 32 1153 1249 32 no draft-ietf-hpke-pq-04
0x0051 MLKEM1024-P384 32 1665 1665 32 no draft-ietf-hpke-pq-04
0x0052-0x6479 Unassigned
0x647A X-Wing 32 1120 1216 32 no draft-connolly-cfrg-xwing-kem-06
0x647B-0xFFFF Unassigned

HPKE KDF Identifiers

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Christopher Wood, Richard Barnes

Reference

Request an Assignment

https://www.iana.org/form/protocol-assignment

Available Formats

Value KDF Nh Two-Stage Reference
0x0000 Reserved N/A N/A RFC-ietf-hpke-hpke-06
0x0001 HKDF-SHA256 32 Y RFC 5869
0x0002 HKDF-SHA384 48 Y RFC 5869
0x0003 HKDF-SHA512 64 Y RFC 5869
0x0004-0x000F Unassigned
0x0010 SHAKE128 32 N draft-ietf-hpke-pq-04
0x0011 SHAKE256 64 N draft-ietf-hpke-pq-04
0x0012 TurboSHAKE128 32 N draft-ietf-hpke-pq-04
0x0013 TurboSHAKE256 64 N draft-ietf-hpke-pq-04
0x0014-0xFFFF Unassigned

HPKE AEAD Identifiers

Registration Procedure(s)

  • Specification Required

Expert(s)

  • Christopher Wood, Richard Barnes

Reference

Request an Assignment

https://www.iana.org/form/protocol-assignment

Available Formats

Value AEAD Nk Nn Nt Reference
0x0000 Reserved N/A N/A N/A RFC-ietf-hpke-hpke-06
0x0001 AES-128-GCM 16 12 16 GCM
0x0002 AES-256-GCM 32 12 16 GCM
0x0003 ChaCha20Poly1305 32 12 16 RFC 8439
0x0004-0xFFFE Unassigned
0xFFFF Export-only 0 0 N/A RFC-ietf-hpke-hpke-06